Project VulcanCentaur

[DaveS]

I a couple of weeks ago the news that Roskosmos sent its engineers to fix the errors of the raptor engine

Raptor is SpaceX and only used on Starship and its booster. And Roscosmos have nothing to do with Starliner which is Boeing's creation.

 

[francisdrake]

Just a short update on what is going on: Making some tests for a non-fairing variant. These special payload adapters will probably have to be tailor-made for each spacecraft.

Trying to implement a pitch-autopilot to ease orbit injection, but this will take some time. Currently I get all bad habits of ill-designed control loops, like over- and under-steering, oscillation around the target value, and so on.

Also the Vulcan Centaur seems to have an unusual flight profile. Towards the end of the core stage burn, the stack needs to pitch up a lot, to gain vertical speed. This is because the thick Centaur is so under-powered with its 2 RL-10 engines, so it would drop back into the atmosphere otherwise.
Maybe this will be countered by fully fueling the Centaur only for the heaviest payloads, and partial fueling for all others.
This will be interesting to learn when the first flight profiles or real launch data become available.

 

[francisdrake]

New version 04 on the front page!

Whats new: Added a very basic launch autopilot. Starts with [V}. It controls the pitch of the first stage only. It performs the ascent pitch-over and the upward kick at the end of the 1st stage burn.
The Centaur still has to be controlled manually.

The autopilot is somewhat useful for the 0, 2 and 4 SRB variants, but ends up too high for the 6 SRB configuration. Still a lot of work to do here.

Other minor improvements are tank venting while still on the ground and non-fairing scenarios for the Star Liner and the Dream Chaser.

Have fun to fly and let me know on your experiences!

 

[CurlSnout]

This one is great fun! After multiple attempts (and fails) I finally achieved stable (if eccentric) orbit in the Dream Chaser using the VC6N variant.





Thanks for this.

Peace,

cs

 

[barrygolden]

Super job working with dream chaser but you might look at the shooting star as well with this

 

[francisdrake]

Thanks for the nice words!
I am playing around to make a Tenacity Dream Chaser (cargo version) with the Shooting Star module.
Needs the six booster version VC6L with the long fairing.
The Dream Chaser is a freely available model by HappyEnte.
I just put a black over the cockpit to simulate the cargo version.

 

[Sbb1413]

Raptor is SpaceX and only used on Starship and its booster. And Roscosmos have nothing to do with Starliner which is Boeing's creation.

He was probably confused with the Raptor engine (used on Starship) and the BE-4 engine (used on Vulcan, made by Blue Origin) as both engines run on liquid methane and LOX. However, a major difference between them is the BE-4 uses a simple staged combustion cycle, while the Raptor uses a complex full-flow staged combustion cycle.

Side note: I have just heard that Rocket Lab's Neutron rocket will run on an open-cycle methalox engine, and although it is less efficient than the BE-4 or the Raptor, its manufacturing cost is said to be lower than the two.

 

[barrygolden]

where or when can we download that new DC and you might put some windows in it as well for a manned version. The Hermès Cockpit would look good in it as well

 

[francisdrake]

where or when can we download that new DC ...

That will still be a few weekends from now.
Main reason are the RCS nozzles of the Dream Chaser being off the mass center. I try to balance that with slightly different thrust levels, and this is tedious. Not balancing would lead to unwanted rotation during translation, which makes docking nearly impossible.

Also will look into the reverse view required for docking. This view direction reverses the action of the left-right and roll thruster keys.

 

[CurlSnout]

For fun, have been playing around with VC variants and alternative payloads - which may or may not be sanctioned by ULA.

1) Kulch's space tug 'DM-2':





2) Kulch's space tug 'Smerch':





3) igel's Molniya-1:





Hi-Ho,

cs

 

[Gargantua2024]

Also will look into the reverse view required for docking. This view direction reverses the action of the left-right and roll thruster keys.

I think Dream Chaser Cargo will be grappled by the Canadarm2 and then berthed to the station via CBMs similar to Cygnus and Cargo Dragon 1, but yeah the controls will be reversed due to that aft docking orientation

 

[CurlSnout]

With Thomas Ruth's Hermes spaceplane:







Hi-Ho,

cs

 

[francisdrake]

@CurlSnout: This is an impressive collection of third-party addons on the VulcanCentaur!

I'd have a few questions:
Do you fly the launcher manually to orbit, or are you using the 'V' command?
How high are the masses of these payloads?
Do you struggle to reach orbit, or is it easy?

 

[CurlSnout]

Ahoy, francisdrake!

First, many thanks for conjuring, and sharing, your VulcanCentaur project. I have been having fun, testing various payloads for traffic into orbit. I must confess that my approach has been pretty simple and strictly empirical - rather than exhaustive and systematic. Essentially, I have been asking, "Can I stick this on top of francisdrake's VC and get it into orbit?" Nevertheless, I will try to answer your questions.

1) For the most part I have been flying the launcher manually. I use the 'V' command to start the engines and get off the pad, but take over after SRB separation. I have mostly employed the 6 SRB configuration, and I found that if I just use 'V' and sit back and watch, the launcher never recovers from the ascent pitch-over and instead reenters the atmosphere.

2) Here is a (partial) list of payload masses:

Kulch's (Yuri Kulchitsky's) DM-2 space tug (from the user manual):

dry mass = 3.0 mT
main fuel mass = 15.0 mT
RCS fuel mass = 1.5 mT

full starting mass = 19.5 mT


Kulch's Smerch space tug (from the user manual):

dry mass = 6.0 mT
main fuel mass = 70.0 mT
RCS fuel mass = 1.5 mT

full starting mass = 77.5 mT


Kulch's Deep Star space probe (from the user manual):

ion drive fuel mass = 2.0 mT
RCS fuel mass = 0.3 mT

total mass = 4.8 mT


Molniya-1 (from Wikipedia):

launch mass = 1.6 mT


Thomas Ruth's Hermes space plane (from the hermes3.ini file):

Mass = 21000


3) With practice (and multiple failures under my belt) I now find it fairly easy to achieve orbit (I admit that often my orbits are not so 'pretty' in that they lack geometric precision). Then again, I have mainly been using the 6 SRB variant and so have the advantage there. I have used the VC4S variant with the DM-2 space tug, and that works fine.

Anyway, I hope some of this might be useful information/feedback. Don't hesitate to ask for clarification. I look forward to any/all updates, as well as future projects from you.

Peace,

cs

 

[Sbb1413]

I have heard that the booster engine section of Vulcan will be reusable (not the booster tank, which will be expended). After jettisoning from the booster tank, the engine section will reenter the atmosphere with a heat shield at the front. Then it will deploy a big parafoil to float in lower atmosphere until a helicopter will catch the engine section.

Of course, this method of recovery (especially the helicopter catching the engine section part) might be unworkable in Orbiter. So, you might skip the helicopter part and let the engine section land with parafoil.

 

[BrianJ]

Of course, this method of recovery (especially the helicopter catching the engine section part) might be unworkable in Orbiter. So, you might skip the helicopter part and let the engine section land with parafoil.

Yes, can be done in Orbiter (see mid-air recovery of Genesis SRC by AS350 helicopter).

 

[francisdrake]

Update 05 on the front page!

Added a flyable version of the Tenacity Dream Chaser (with the Shooting Star cargo module) as a separate download.
The solar panels can be extended with (S) and the wings can be spread with (W). Other keys are in the documentation. Rearward docking is a little tricky, as the RCS thrusters are reversed.

For the launch scenario, both the VulcanCentaur and the Tenacity need to be installed.
The aerodynamics for landing are borrowed from the DeltaGlider. The real Dream Chaser is probably less maneuverable.

@CurlSnout: Thanks for the flight data! This Tenacity has about 19 ton dry + 5 ton wet mass, for comparison.

 

[CurlSnout]

Finally had some free time in which to give the new update a go. Very wonderful! Many thanks for this. What's next?

 

[barrygolden]

Looks super and flys pretty good. Might need to ad some windows for a manned version as well.
Where do I download the Alpaca ?

 

[barrygolden]

This new Dream Chaser needs some decals as well. Might be good to do the black one as well and the Blue solar panels are a good touch. There is a plan to land this at Ellington Field near JSC